Viswasam (transl. Loyalty) is a 2019 Indian Tamil-language action drama film directed by Siva and produced by Sathya Jyothi Films. The film stars Ajith Kumar, Nayanthara and Jagapathi Babu in the lead roles, alongside Vivek, Thambi Ramaiah, Robo Shankar, Kovai Sarala, Yogi Babu, Anikha Surendran, Kalairani, Sujatha Sivakumar, Rajitha and R. N. R. Manohar. It is the second collaboration between Ajith with Siva out of three films. The film follows Thookudurai, a villiage ruffian, who goes to take on Gautham Veer after trying to patch his marriage with Niranjana.

The film was officially announced in November 2017 under the tentative title Thala 58, as it is Ajith's 58th film as leading actor, and the official title was announced a few days later. Principal photography commenced in May 2018. It was predominantly shot in Chennai and Hyderabad before wrapping by mid-November 2018. The film has music composed by D. Imman, cinematography handled by Vetri Palanisamy and editing by Ruben.

Viswasam was released worldwide on 10 January 2019 in theatres to mixed reviews from critics. Imman won Best Music Director at the 67th National Film Awards. The film was also a commercial success, grossing around ₹185-200 crore, thus ranking among the highest grossing South Indian films of 2019 and securing the position of the third highest grossing Tamil films of 2019.